Concise and Efficient Access to 5, 7‐Disubstituted Pyrazolo[1, 5‐a]pyrimidines by Pd‐Catalyzed Sequential Arylation, Alkynylation and SNAr Reaction. Issue 41 (6th November 2017) - Jismy, Badr
Abstract : A simple and efficient method for synthesis of 5, 7‐disubstituted pyrazolo[1, 5‐ a ]pyrimidines is reported. The synthetic route involved first a one‐pot two‐step synthesis of 7‐substituted pyrazolo[1, 5‐ a ]pyrimidin‐5‐ones from the reaction of 3‐aminopyrazole1 with activated alkynes. These compounds were used as key intermediates to access, with excellent yields, a library of new 5, 7‐disubstituted pyrazolo[1, 5‐ a ]pyrimidines, which are known for their wide range of biological activities, through C–O bond activation with PyBroP (bromotripyrrolidinophosphonium hexafluorophosphate) as an activator reagent. Abstract : Synthesis of new 5, 7‐disubstituted pyrazolo[1, 5‐ a ]pyrimidines from 3‐aminopyrazole and activated alkynes through C–O bond activation is described.